Definitions Flashcards
Metabolism
The chemical pathways and reactions that result in the breakdown of molecules (catabolism, or catabolic pathways) or synthesis of molecules (anabolism, or anabolic pathways)
Respiration
Set of metabolic reactions and processes that take place in the cells to convert biochemical energy from nutrients into ATP
Catabolic Reactions
Reactions that PRODUCE ATP
Anabolic Reactions
Reactions that USE ATP
Oxidation
Electron is removed from an atom or molecule
Reduction
Addition of electron from an atom or molecule
Glycolysis
Oxidation of glucose to produce pyruvate
Glycogenolysis
Breakdown of glycogen to yield glucose, which is oxidized to pyruvate
Glycogenesis
Synthesis of glycogen
Contractile proteins
Actin and Myosin
Structural Proteins
Titin, Destine, Dystrophin and Integrin
Titin
attaches end of filaments too Z line (it is elastic)
Desmin
Joins Z lines between adjacent myofibrils
Dystrophin and integrin
membrane stabilizing proteins (connect to sarcolema)
Process of muscle contraction (excitation contraction coupling)
Nerve stimulates muscle to generate an action potential
Action potential in muscle stimulates release of calcium from SR
Calcium binds with troponin, causing change in the conformation (shape) of actin
Change in shape exposes the myosin binding sites on actin; myosin interacts with actin and begins cross bridge cycling
Contraction terminates when AP stops, and Calcium is taken back up into the SR
Role of ATP in cross bridge cycling
Hydrolysis of ATP provides energy to move myosin head into high energy configuration
Re-synthesis of ATP causes cross bridge to detach
Cardiac Cells
Are connected at intercalated discs; when one cardiac myocyte is stimulated to contract, signal travels to all interconnected cardiac myocytes causing them all to contract at the same time (syncytium)
Smooth muscle
Smooth muscle twitch is much slower than skeletal or cardiac muscle twitch (calcium pumping by SR is slower, phosphorylation/de-phosphorylation steps are slower, and requires more ATP to move myosin head)
Smooth muscles can remain contracted even without ATP re-synthesis (or with very slow rate of ATP turnover)
Mechanoreceptors
Sense movement within joints; accelerates HR to meet demands of exercise
Chemoreceptors
Sense changes in chemical state within muscle; accelerates HR to meet demands of exercise
Baroreceptors
Sense changes in blood pressure in carotid artery and aortic arch; negative FB system that buffers beat-to-beat fluctuations in arterial pressure from and internal set point or baseline value
Rate Pressure Product (Double Product)
an index of myocardial oxygen consumption
RPP=HRxSBP
Used to prescribe safe exercise zones in individuals with hypertension
Pre-load
End Diastolic Volume
Volume in LV at end of diastolic filling phase, prior to systole (contraction)
After-load
Volume in LV at end of systole (not all blood will be ejected)
Stroke Volume
Preload- Afterload
Amount of blood ejected each beat
Ejection Fraction
% of preload that is ejected during systole
Diastolic Dysfunction
Reduced compliance of the ventricles during diastolic phase (reduced relaxation capacity, reduced compliance of myocardial tissue, pericardial restriction) Can be caused by: age HTN Diabetes Ischemia HD
Cardiac output
The amount of blood ejected from the left ventricle into circulation in L/min
CO (Q)=HRxSV
At rest Q is about 5 L/min
Maximal CO during exercise is ~35-40 L/min
Mean Arterial Pressure
Average perfusion pressure delivered to organs
Normal is 70-110 mmHg
DBP+.33*PP
